berrian



Dec. 8, 1959 J, H, BERRlAN 42,915,983

TUBING PUMP Filed Aug. 10, 1956 Amie.-

BY wf Wa@ ATTORNEY United States Patent TUBING PUMP James H. Berrian,Bethesda, Md.

Application August 10, 1956, Serial No. 603,453

Claims. (Cl. 103-149) (Granted under Title 35, U.S. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

The present invention relates to tubing pumps and more particularly to atubing p-ump in which a section of tubing is progressively compressed bya rigid surface so that a relatively steady flow is obtained.

'Various sorts of tubing pump devices which are capable of the samegeneral function as the present invention are prevalent in the priorart. In these devices the contents of a tube are forced to ow -by meansof rollers, screws, lingers or cones brought to bear upon the tubing,but these devices, while capable of low speed operation, were notdesigned for and are not capable of sustained high speed and highdelivery rate operation. In many of the prior art devices the tubingcreeps or abrades quite badly, and the devices are not adaptable to awide range of tubing sizes and materials. many of the prior art devicesalso leave something to be desired as the flow is often highly pulsatlein character and the devices are subject to some backow during a portionof each pumping cycle. A number of the prior art devices are quitecomplicated mechanically and are thus prone to many minor defects whichrequire an overabundance of maintenance and repair work.

The p-resent invention provides a tubing pump capable of continuous highspeed and high delivery rate operation in which a piece `of flexibletubing is placed between a rubber or other compression plate and a`gyrating cone which is driven by an eccentric cam. As the eccentric camrotates different portions of the periphery of the cone are raised tocompress the tubing progressively between the cone and the resilientcompression plate. The liquid which is being pumped is forced along thetubing ahead of the portion of the tubing which is occluded by theaction of the cone and the compression plate, and behind such portion avacuum is left which causes fresh liquid to be forced into the tubing.The tubing is arranged in spiral form extending over an arc of more than360 so that a portion of the tub-ing overlaps the inlet. The`overlapping of the tubing prevents backflow and provides a substantialeven flow without appreciable pul- 'sations. The cone of the presentinvention is restrained against rotation and different portions of theperiphery thereof are raised successively to compress the tubing,therefore the creeping or abrading of the tubing is elim- The llowcharacteristics of i inated. The rubber compression plate also allowsthe ice when the pump is operated at very high speeds and pressures.

An object of the present invention is the provision of a tubing pump forpumping blood and other sterile liquids.

Another object is to provide a tubing pump for pumping radioactive orcorrosive liquids and gases.

A further object of the invention is the provision of a tubing pumpcapable of sustained high speed and high delivery rate operation.

Still another object of the invention is to provide a high speed tubingpump which is mechanically simple and has a minimum of moving parts.

A further object of the invention is the provision of a tubing pump inwhich the discharge flow is relatively free of pulsations and in whichbackllow is eliminated.

Another object of the invention is the provision of a tubing pump inWhich the drive mechanism and bearings are protected from contaminationin the event of a rupture of the tubing carrying the fluid.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawing in which like referencenumerals designate like parts throughout the figures thereof andwherein:

Figure 1 shows a plan View of a preferred embodiment of the invention,with a portion of the base plate cut away.

Figure 2 shows a section of the device taken along line 2 2 of Figure 1looking in the direction of the arrows.

Figure 3 shows an elevational view of the device with a portion of thecasing cut away.

Referring now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout the several views,there is shown in Figs. 1 3 (which illustrate a preferred embodiment) atubing pump generally designated by the numeral 11 comprising a casing12 which has an axial bore 13 therethrough adapted to receive a driveshaft 14, which may be driven by any suitable source of power such as avariable speed electric motor, not shown.

A beveled cylinder 15 is coaxially mounted upon the drive shaft 14, saidbeveled cylinder carries an eccentric cam shaft 16, the axis of which isoffset and forms an angle with the axis of the drive shaft 14. The driveshaft 14 is mounted in the casing 12 by means of a roller bearing whichhas an outside race 17 securely fixed in the casing 12, an inside race18 fixed to the drive shaft 14 and rollers 21 between the two races.

The inside race 22 of another roller bearing assembly is pressed overthe cam shaft 16 and abuts the beveled surface of the beveled cylinder15; the -outer race 23 of said bearing assembly which has rollers 29positioned between the two races carries a cone shaped element 24 havinga depending circular flange 25 on its under surface into which the outerrace 23 of the roller bearing assembly fits. In the upper side of theconical element a circular groove 26 is cut which has an arcuate outerface 27 adapted to receive a complementary crowned ring 28 which dependsfrom a base or cover plate 31. The upper side of the conical surpacealso has a semi-spherical socket 33 adapted to receive a ball bearing34. As previously pointed out, a base plate 31 is provided to fit overthe open end of the casing 12 and is affixed thereto by any suitablemeans, for example, a stud 35, with a stud pin 36 passing therethroughto prevent its rotation, mounted in the casing 12 and a locking nut 37adapted to coact with the threaded portion of the stud 35. The baseplate 31 may be provided with a depending flange 32 at its periphery asshown in Figs. 2 and 3. The base plate 31 also has a semi-sphericalsocket 38 cut into its under side to receive the ball bearing 34. These'.'-sph'erical socket 33 in the upper surface of the cone is somewhatless than half a sphere so that the cone 24`will be capable ofgyratingrabout the -ballbearing 34. Referring now to Figure 2, there isshown a Yresilient compression plate 41, prefer ably formed of rubber,but which may be constructed of any suitable resilient material affixedto the base plate 31 and positioned between the dependingcrowned ring 28and the outer depending flange 32 of said base plate; Positioned betweenthe cone 24 and the resilient compression plate 41 is a flexible tubing42 made of any suitable material such as rubber or plastic, saidflexible tubing enters the pump by means of port 43fin the base plate 31and leaves the pump byarneans of a similar port 44. Tubing access slots45 and 46 are provided inthe base plate 31 to permit exible'tubing 42 tobe readily removed and replaced;A As can best be seen by references toFigure l this flexible tubing circumscribes anV arc of more than 360;this arrangement ensures delivery over an entire cycle, except for asmall angle of rotation as Ythe sector of occlusion passes over theoutlet port, and it also prevents momentary backflow. Y

It can be seen by reference to Figures 2 and 3 that the inner face 47 ofthe wall of the casing 12 is of arcuate configuration, the curvature ofsaid arc being determined by the path of the periphery of the cone 24 asit gyrates. The outer surface 48 of the cone 24 is properly machined tot the configuration of the inner face 47` so` that the clearance betweenthis outer surface and the ginner face of the casing wall is kept lat aminimum. The flexible tubing 42 is very tightly Vconfined between thecone 24 and the compression plate 41 and because of the close fitbetween the complementary surfaces 27 and 28 and l the surfaces 47 and48 the tubing cannot rupture due to high pressures and it cannot becomepinched or abraded. This enables the pump to be operated at extremelyhigh pressures.

A resilient sleeve 51, made of a suitable material such as -rubber orneoprene isA affixed to an inner portion of the casing 12 by means of ametal retaining ring S2. This is a very important feature of theinvention 4as it prevents the liquid from contaminating the bearings inthe event the flexible tubing 42 should rupture. In this regard a drainhole `53 Ais provided in the bottom of the casing 12 so that the liquidmay be drainedl from the pumpin event such rupture does occur.`Referring now to Figure 2 it can 'be seen that the axis of the driveshaft 14 and the axis of the cam shaft 16 intersect at the center of theball bearing 34A and that the angle between the two axes is the same asthe greatest angle between the compression yplate 41 and the plane ofthe conical surface 24. Thecenter ofthe ball bearing 34 is thus thecenter of gyration for the cone 24. The radius of curvature of thecompressing face of the cone 24 is made suiciently large so that theflexible tubing is occluded over an appreciable sector, and thus thetube is sealed against backflow at any angular positionof the driveshaft.

In operation, the drive shaft 14 is rotated by a suitable source ofpower, which in turn rotates eccentric cam shaft 16 and the motion istransmitted to the coneV 24 by means of the roller bearing locatedbetween the cam The cone then gyrates about the f l shaft Vandsaid cone.center of the ball bearing 34. The friction between the cone 24 andthetubing -42 and the rotational friction between the ball bearing 34andthe cone 24 is greater than the friction in the roller bearingbetween the cam shaft `16 and the cone thus the cone is restrainedagainst rotation. As the cone'24V gyra'tes diiferent points on theperiphery thereof are raised to compress the tubing 42 progressivelybetween. the cone and theV resilientcompression plate 41. The liquidwhich is being pumped is forced along the tubing ahead of the portionwhich is occluded by the action of the-cone and the compression plateand behind such occluded portion a vacuum is left which permits `freshliquid to be forced into the tubing. By reference to Fig. 2 it canreadily be ascertained that any given point on the cone 24 oscillatesabout the center of gyration of the conc-center of ball bearing34-moving toward and away from an opposed point on the resilientcompression plate `41. As the gyration proceeds a rolling action isproduced which compresses and expands the tube progressively along itslength and advances the iluid through the tube.

By selecting a rubber or other resilient material of suitablecomposition for the compression plate 41 and mak ing it of the properthickness a wide range of tubing wall thicknesses can be accommodatedwithout changing the ring. It has been found that a rubber of mediumtexture is best for general overall use. The maximum delivery rate ofthe pump can be effectively regulated by using compositions of differentresiliencies. If a composition of low resiliency is used muchl higherdelivery pressure and hence greater ows can be obtained than i-f ahighly resilient composition were used. For example, if a highlyresilient material such as sponge rubber isiused, the maximum deliverypressure may be on the order of only l0 p.s.i., whereas, if a very hardrubber composition is used maximum delivery pressures in theneighborhood of 40 p.s.i. are obtainable.

It should be pointed out'that this pump is very satisfactory for thepumping of human blood as the amount of hemolysis is sufliciently low tomeet medical standards; in fact, in tests run by .the inventor, theamount of hemolysis was considerably lower than had previously beenrecorded for known pumps. It yis thought that the elimination of backflow, the use of tubing of large internal diameter and having a largeradius of curvature when installed in the pump, plus the substantialelimination of pulsatile ow contributes substantially to the inhemolysis. l

It should be understood, of course, that the foregoing disclosurerelates to only a preferred embodiment of the invention and that it isintended to cover all changes and modifications of the example of theinvention herein chosen for the purposes of the disclosure, whichdo notconstitute departures from the spirit and scope of the invention set,forth in the appended claims. What is claimed is:

1. In a tubing pump, a casing, a member having a conical face mountedfor gyratory movement within said casing, driving means for said member,a cover plate having a resilient face covering said casing, bearingmeans comprising a single ball positioned in sockets formed in saidmember mounted for gyratory movement and said cover plate, the center ofsaid bearing means being coincident with the center of gyration of saidmember mounted for gyratory movement, and a flexible tubing having anover# reduction Y lapped loop formed between inlet and outlet portionsthereof, said loops being positioned between the resilient face of saidcover plate and the conical face of said member mounted for gyratorymovement. 5

2. In a tubing pump, a casing, a member mounted for y gyratory movementwithin said casing, a cover plate covering vsaid casing, bearing meanscomprising a single ball mounted in sockets in said member mounted forgyratory movement and said cover plate, the center of said bearing meansbeing coincident with the center of gyration of said member mounted forgyratory movement, resilient means positioned between said cover plateand said member mounted for gyratory movement and a exible 'tubinghaving a loop `formed between inlet and outlet portions thereof, theloop being positioned between said resilient meansV and saidmembermounted for gyratory movement.

3. In a tubing pump, a casing, a member mounted for gyratory` movementwithin said casing, a cover'plate covering said casing, drive means forsaid member passing through said casing, bearing means located betweensaid casing and said drivemeans and `between said drive means andsaidmember mounted for` gyratory movement, a exible tubing having a loopbetween inlet and outlet portions thereof, the loop being positionedbetween said cover plate and said member mounted for gyratory movement,and a flexible sleeve surrounding said bearing means and positionedwithin the casing in sealing engagement with said member and said casingto shield said bearing means from the contents of said flexible tubingshould said flexible tubing rupture.

4. In a tubing pump, a casing having an open end, a member having aconical surface positioned within said casing, means for imparting agyratory motion to said member including bearings positioned betweensaid casing and said member, a cover plate covering said casing, bearingmeans comprising a single ball and sockets therefor in said memberhaving a conical surface and said cover plate, the center of saidbearing means being coincident with the center of gyration of saidmember, resilient means positioned between said cover plate and saidmember having a conical surface, a flexible tubing having a loopbetweeninlet and outlet portions thereof and positioned between saidresilient means and said member having a conical surface, and ilexiblemeans surrounding the bearings which are included in the gyratory means,to protect said bearings from contamination in event of a rupture ofsaid iiexible tubing.

5. In a tubing pump, a casing, a drive shaft mounted in said casing,bearing means interposed between said casing and said drive shaft, aneccentric shaft extending from said drive shaft in said casing andoffset at the juncture thereof with said drive shaft, the upper end ofsaid eccentric shaft extending angularly toward and above the axis ofrotation of said drive shaft, a gyratory member having a conical surfaceand mounted for non-rotating gyratory motion on said eccentric shaft,bearing means interposed between the eccentric shaft and the gyratorymember, a cover plate mounted on said casing, a single ball set in saidcover plate `and in said gyratory member and aligned with said axis ofrotation for firmly supporting said gyratory member, and a length offlexible tube having a looped portion interposed between said coverplate and the conical surface of said gyratory member whereby the loopedportion of said tube is progressively compressed and released, the endsof said tube extending exteriorly of said casing and through said coverplate.

References Cited in the le of this patent UNITED STATES PATENTS1,848,024 lOwen Mar. l, 1932 2,249,806 Bogoslowsky July 22, 19412,534,855 Corneil Dec. 19, 1950 2,752,852 `Oiutt July 3, 1956 FOREIGNPATENTS 7,844 Great Britain of 1938

